The AGN STORM (space telescope optical reverberation mapping) was an intense multi-wavelength campaign that observed NGC 5548, a type I Seyfert galaxy (z = 0.01717), for 180 months during 2014. The main goal was to determine the geometry and mass of the object through the reverberation mapping method, using 6 space-based and 21 ground-based telescopes.

NGC 5548 exhibited unusual behavior during the campaign: First, a strong soft X-ray absorption was present due to the appearance of a line of sight (LOS) obscurer between the central source and the observer. Then, it was discovered that broad emission lines and the UV continuum (emission-line holiday) decorrelated for 2 months during the observations. Finally, it was discovered that the same decorrelation happened between the narrow absorption lines and the continuum (absorption-line holiday).

We joined the campaign in 2017 to understand the behavior of NGC 5548 during the time of obscuration and holiday. We showed that LOS obscurer is the upper part of a symmetric continues disk-wind launched from the accretion disk. The base of this wind is called the equatorial obscurer and it persistently shields the BLR.  Based on Cloudy’s prediction, the variations of the covering factor of the LOS obscurer explains the absorption-line holiday, while changes in the column density/density of the equatorial obscurer explain the emission-line holiday.

Recently, we found out that the base of the wind has significant optical depth to electron scattering and must be a contributor to the Compton reflector. This reflector acts as a mirror and would reflect BLR emission. The wind’s optical depth explains why the far sides of the BLR are unexpectedly faint. During this talk, I will explain how our modeling resulted in this discovery, and also how the disk-wind model scenario fits into observations. 

The AGN STORM (space telescope optical reverberation mapping) was an intense multi-wavelength campaign that observed NGC 5548, a type I Seyfert galaxy (z = 0.01717), for 180 months during 2014. The main goal was to determine the geometry and mass of the object through the reverberation mapping method, using 6 space-based and 21 ground-based telescopes.

NGC 5548 exhibited unusual behavior during the campaign: First, a strong soft X-ray absorption was present due to the appearance of a line of sight (LOS) obscurer between the central source and the observer. Then, it was discovered that broad emission lines and the UV continuum (emission-line holiday) decorrelated for 2 months during the observations. Finally, it was discovered that the same decorrelation happened between the narrow absorption lines and the continuum (absorption-line holiday).

We joined the campaign in 2017 to understand the behavior of NGC 5548 during the time of obscuration and holiday. We showed that LOS obscurer is the upper part of a symmetric continues disk-wind launched from the accretion disk. The base of this wind is called the equatorial obscurer and it persistently shields the BLR.  Based on Cloudy’s prediction, the variations of the covering factor of the LOS obscurer explains the absorption-line holiday, while changes in the column density/density of the equatorial obscurer explain the emission-line holiday.

Recently, we found out that the base of the wind has significant optical depth to electron scattering and must be a contributor to the Compton reflector. This reflector acts as a mirror and would reflect BLR emission. The wind’s optical depth explains why the far sides of the BLR are unexpectedly faint. During this talk, I will explain how our modeling resulted in this discovery, and also how the disk-wind model scenario fits into observations. 

I will report on the most recent discoveries by the NASA Neil Gehrels Swift mission of Active Galactic Nuclei (AGN) with high amplitude variabilities. While AGN typically vary with factors of 3 on times scales of days to years, some AGN exhibit outbursts or dramatic drops in the X-ray fluxes by factors of even more than 100. Among the most extreme cases are the Narrow-Line Seyfert 1 galaxy WPVS 007 which appears to be extremely X-ray faint, and the Seyfert 1.9 galaxy IC 3599 which has shown repeated X-ray flaring, most likely due to accretion disk instabilities. Swift capability of following objects for more than a decade with simultaneous X-ray and UV observations has allowed us to discover several of these extreme AGN.  Recent examples are IRAS 23226-3843, RX J2317-4422 and repeatedly Mkn 335 on which we triggered XMM/NuSTAR and HST observations several times in 2018 and 2019. In particular IRAS 23226-3843 is a so called changing look AGN that has changed its optical spectroscopic type several times. In most recent Swift observations IRAS 23226-3843 was found to be flaring again.

I will report on the most recent discoveries by the NASA Neil Gehrels Swift mission of Active Galactic Nuclei (AGN) with high amplitude variabilities. While AGN typically vary with factors of 3 on times scales of days to years, some AGN exhibit outbursts or dramatic drops in the X-ray fluxes by factors of even more than 100. Among the most extreme cases are the Narrow-Line Seyfert 1 galaxy WPVS 007 which appears to be extremely X-ray faint, and the Seyfert 1.9 galaxy IC 3599 which has shown repeated X-ray flaring, most likely due to accretion disk instabilities. Swift capability of following objects for more than a decade with simultaneous X-ray and UV observations has allowed us to discover several of these extreme AGN.  Recent examples are IRAS 23226-3843, RX J2317-4422 and repeatedly Mkn 335 on which we triggered XMM/NuSTAR and HST observations several times in 2018 and 2019. In particular IRAS 23226-3843 is a so called changing look AGN that has changed its optical spectroscopic type several times. In most recent Swift observations IRAS 23226-3843 was found to be flaring again.

AGNs are the brightest persistent source of the electromagnetic radiation in the universe, enabling us to discover and study them across the cosmos. These are in the central regions of galaxies, and observing and tracing them informs us of the role of supermassive black holes (SBH) in the formation and evolution of galaxies. Fundamental properties such as the mass of the SBH and correlations with luminosity are based upon line-continuum reverberation mapping. Time delays between changes in the continuum luminosity and the response of the emission lines measure the physical size. The method is the basis for understanding phenomena near the SBH, which are far too small to be resolved even with the best telescopes.

During this talk, I will discuss how this correlation was broken in one of the well-studied AGNs, namely AGN NGC 5548.  In this object, the soft X-ray part of the SED was dramatically extinguished by an obscurer. During part of the time that this obscurer was present, the absorption and emission lines did not respond to variations of the continuum. We modeled the decorrelation of the absorption lines from the continuum in terms of a varying obscurer covering factor, and identify the physics which makes this possible. We identify a cycle in which the soft X-ray portion of the SED varies, causing changes in the ionization of helium.  The ionizing radiation produced in its recombination governs the ionization of the species observed with HST.  Photoionization models reproduce the sense of HST observations.  The obscurer is likely to be part of the broad-line region which happens to cover our sight line to the central object.  This shows the importance of cloud shadowing in understanding the physics of the emission-line clouds. 

The field of exoplanets and low-mass companions is being revolutionized by large scale surveys. In this talk, I will discuss one on-going and one planned large scale survey. The first of these are the APOGEE-I and APOGEE-II surveys. The APOGEE surveys continue to expand the scale of low-mass radial velocity (RV) companion searches. This includes recent work from the APOGEE radial velocity group on the detection of a gold sample of RV companions, and insight this sample provides on the question of the brown dwarf desert. The second half of my talk will focus on the on-going preparation for the TESS all-sky transit survey, which will launch in late 2017. My work on this consists primarily in helping to develop the TESS Input Catalog. Finally, I will look at future ways in which APOGEE and TESS can complement each other and discuss TESS Follow-up Opportunities.

The Milky Way's dust is of basic importance in astronomy. It is both crucial to the formation of stars and a pervasive observational nuisance. Despite the dust's importance, existing dust maps are largely limited to two dimensions, with the distance to the dust unknown. The advent of large surveys like Pan-STARRS1 has allowed us to map dust in three dimensions in unprecedented detail. In this talk, I will describe how we use observations of stars in the Milky Way to map dust, and I will discuss three major results: a catalog of distances to major molecular clouds, the discovery of a 100 pc ring of dust in Orion, and the 3D dust map itself. Upcoming surveys promise continued scientific returns: Gaia, DECam, and the LSST will provide more precise and deeper data than ever before, enabling unique maps of the Galaxy's spiral structure and the study of the dust's properties in 3D.